1. Field of the Invention
The present invention relates, generally, to a vehicle seat and, more specifically, to vehicle seat having a backrest assembly that locks the backrest in both an upright and a folded down position.
2. Description of the Related Art
Seat assemblies having reclining or pivoting backrests are a popular component in many automotive vehicles. Seats with pivoting backrests are used commonly in two-door vehicles to provide access to the rear seat. Rear seats in hatchback type, 3 or 5-door vehicles are often designed to pivot forward and fold down flat to provide additional cargo area. In some instances, vehicle seat backrests are designed to both recline for passenger comfort and also fold down for greater storage space. Seats of this type may be installed as a rear seat in a sedan or as the intermediate and/or rear seat of a van or sport utility vehicle. In these types of seating arrangements, the combined reclining and pivoting mechanisms can be quite bulky and cumbersome.
A pivoting vehicle seat backrest requires a pivoting mechanism that allows for the selective forward rotation of the backrest between an upright seating position and a folded-down storage position. The pivot mechanism must have its axis placed so that the seatback will fully fold down upon the bottom seat cushion. Additionally, the pivoting backrest also requires a locking mechanism to secure the backrest in its upright position. The pivoting mechanism is known in the art as a “dumplatch,” this term is derived from the act of “dumping” the seatback from the upright position to a forward folded position. A reclining vehicle seat backrest requires a reclining mechanism that allows for the selective rearward rotation of the backrest from the fully upright seating position to any of a variety of more reclined seating positions based on the desires of occupant. The reclining mechanism has its own locking components, which are inherent in the selective positioning structure of the device.
When it is desired to construct a backrest that incorporates both the ability to pivot forward for storage and the ability to recline, a reclining mechanism, a pivoting mechanism, and a pivot locking mechanism must all be included in the seat assembly. The conventional approaches taken to combine these mechanisms have been successful to a point. However, there remains room for improvement. Pivoting and reclining mechanisms have generally remained separate mechanisms in close proximity to each other at the juncture between the seat backrest and the seat bottom. This separation of the mechanisms is generally due to the fact that the axis of rotation for pivoting the seat must be higher and forward of the reclining axis to provide for a more compact size when folded. When a reclining but non-pivoting seat is folded forward about its reclining axis of rotation, the base of the seat backrest and the bottom seat cushion interfere with each other and impede the folding action.
Since the pivoting and reclining mechanisms have generally remained separate components, most of the conventional attempts at improving the design of the backrest of the seat assembly relate to more efficiently incorporating the pivot locking mechanism into the seat assembly. One approach has been to provide separate locking assemblies at the top of the backrest that interact with fixtures on the floor of the vehicle and at an upper locking point in the vehicle pillar area. When upright, this requires the seat backrest to remain in one position or have a limited range of movement, which negates most of the reclining ability. This function typically requires separate components that are vehicle specific and that interfere with passenger ingress and egress to and from the vehicle. In other approaches, the lower locking hardware is omitted to reduce system components and avoid the problems associated with interfering with passenger movement at the floor area. However, omitting the locking mechanism leaves the folded seat backrest unsecured which presents safety issues in the event of an emergency situation, such as a collision or hard braking. Another approach has been to use a dumplatch locking mechanism in which the dumplatch is incorporated into the pivoting mechanism of the seat backrest systems. However, the dumplatch locking assembly of conventional backrest assemblies are typically located forward of the seat pivot point in the seat fold area, which causes them to intrude forward into the seating area, again presenting passenger entry and exit difficulties. The conventional dumplatches also require additional trim pieces to protect the occupants from the mechanism. Furthermore, each of these conventional approaches to improving vehicle seat backrest mechanisms must be specifically tailored to the particular vehicle or a particular vehicle seat, which increases the production costs of the seat.
Therefore, there remains a need in the art for a vehicle seat backrest locking assembly having a pivoting and the reclining mechanism that provides a compact and efficient backrest mechanism and that avoids intruding into the seating area. Additionally, there remains a need for a compact and efficient backrest mechanism that provides reclining, pivoting, and locking features into a universal device that may be employed on a wide variety of vehicle seats and in a wide variety of vehicles.